Edge lighting may be desirable in an aircraft because, in an edge-lit system, a light source and its associated hardware can be placed in a convenient (out of the way) location while a light guide transmits light from the light source to a light emitting surface. On the other hand, backlit systems require the light source to be positioned directly behind the light emitting surface. This makes installation of backlit systems more complicated. For example, backlit systems may require additional wiring in order to have the light source positioned behind the light emitting surface; or in some cases, it may be impossible to install the light emitting surface at a desired location due to wiring and/or spatial limitations.
Acrylics are often used for edge lighting. However, most acrylics do not meet aviation industry standards because they are too flammable to be used on an aircraft. The next viable option would be polycarbonate, which is inherently flame-retardant. However, polycarbonate has a high transmission loss when light travels through it. This material characteristic of polycarbonate renders it a non-ideal material for a light guide. There is a need for new edge lighting solutions, particularly ones that meet aviation industry standards.